Rio Carbon 5 GB MP3 Player 5 GB storage capacity holds up to 2500 songs, 80 hours of MP3 , or 160 hours WMA Plays MP3, WMA, and Audible audio formats Rechargeable battery offers up to 20 hours of battery life on a single charge USB 2.0 for faster downloads; built-in microphone for voice recording Compatible with Windows 98SE, 2000, ME, XP and MAC OS X v10.2 or later